Hi,
I was wondering if it were possible to import text files with marker information into Acqknowledge. For example, if we had a file with a column for the onset and a column with a marker label, would we be able to import this information into Acqknowledge without manually having to append markers? Thanks for your help!
Kristin
Maybe I’m misunderstanding the motivation for importing text files with marker info into acqknowlege, but it strikes me as a very problematic and unnecessary way to accomplish this task. You just need a little bit of hardware to completely automate the process of inserting timing markers into your acqknowledge data-stream (basically, a connector from your stimulus presentation system to your biopac unit).
Importing markers into acqknowledge any other way is going to be potentially problematic, because you are going to introduce more noise into your data, related to the imprecision of the placement of the timing markers. If you were to try to insert markers by merging in a text file (which I don’t actually know how you would do), you would have to worry about making sure that the text file and the acqknowledge data file are completely synchronized with respect to starting time, and that they remain perfectly synchronized over the course of your recording epoch. This is going to be a huge problem if you are trying to measure anything with temporal resolution less than a few seconds. Why bother with such a tedious problem? Why not just buy the correct hardware?
In thinking about it, I’m sure you could come up with a way to merge a file with your timing information into your acqknowledge datastream, but it would be a major pain, and needlessly challenging.
I would imagine that one way you could do it (and I would not recommend doing it) would be to save your acknowledge data as a Matlab file. Then open the data in Matlab–it will be a datafile with different columns for your different biopac channels. However, the data will be in the file at your sampling rate. So for instance, if you have recorded at 250 Hz with Biopac, then you will have one datapoint for every 4 ms (assuming my brain is working at the moment) for every biopac channel (these are large files). So to accurately merge in your timing signal, you’d have to get the data from Superlab in a format that would let you figure out where in the datastream you would insert a new timing signal variable, and you’d need to format the data in Matlab correctly. Again, you would have some uncertainty about whether Superlab and Biopac were perfectly in synch across the recording, given that they were not linked up (they probably wouldn’t be hugely off, but again, there will likely be some noise there–and the extent of the problem depends upon the nature of the data you’re recording and how much temporal precision you need for your analysis).
Again, though, even if you could do it, it would be a giant headache and the results would be questionable. I’d really recommend taking the easier (although slightly more expensive) route of buying the hardware to synch your superlab presentation computer with your acqknowledge recording computer.